Astronomers Confirm Presence of Second Trojan Asteroid on Earth’s Orbit

The second Earth Trojan asteroid was confirmed by astronomers and called it 2020 XL5, according to a new study published in the journal Nature on February 1.

The new study reveals the Trojan asteroid is situated in Earth's orbit. It is estimated that 2020 XL5 will remain in Earth's orbit for more than 3,500 years before it escapes the planet's gravitation.

Trojan Asteroids and the Formation of our Solar System

(Photo : Menahem Kahana via Getty Images)

According to Audrey Martin, NASA's scientist under the Lucy mission, Trojan asteroids are small space rocks that share their gravitational orbit with a planet. The NASA scientist added most of these rocks became Jupiter Trojan asteroids, which are gravitationally trapped in Jupiter's orbit around the sun for billions of years.

Martin also said these asteroids dates back to four billion years ago when our newly formed solar system consisted of trillions of tiny little rocks and icy objects.

A large number of these asteroids combined together to form the planets, but some of these rocks have scattered across the solar system and the universe, says Martin.

The new study's lead author Toni Santana-Ros, a researcher at the University of Alicante and the Institute of Cosmos Sciences (ICCUB) at the University of Barcelona, observed the second Earth Trojan asteroid with the Southern Astrophysical Research (SOAR) telescope in Chile.

Santana-Ros were accompanied by other astronomers who also observed 2020 XL5 with the Lowell Discovery Telescope in Arizona and the European Space Agency's Optical Ground Station in Tenerife, Canary Islands,

Also read: NASA: What are 'Trojan' Asteroids? Fast Facts on the Rare Elusive Space Rock

Earth's Two Trojan Asteroid Companions

The new study published in Nature was more of follow-up research from December 2020, when a separate team of astronomers thought they had found a second Earth Trojan asteroid, in addition to the first Earth Trojan asteroid, called 2010 TK7, discovered in 2010.

In December 2020, a separate team of astronomers first discovered the 2020 XL5 Earth Trojan asteroid using the Pan-STARRS 1 survey telescope in Hawaii, in addition to the International Astronomical Union's Minor Planet Center database.

However, it was not fully understood two years ago whether 2020 XL5 was just a nearby space rock passing through Earth's orbit or if it was a real Earth Trojan asteroid, as per Space.

There are many Trojan asteroids discovered in our solar system, more than 7,000 of these rocks are hanging around Jupiter's orbit as of 2020.

Prior to confirming 2020 XL5 was indeed an Earth Trojan asteroid, there was only one confirmed Earth Trojan asteroid on Earth, called 2010 TK7. The latest discovery imply that Earth will have two Trojan asteroid companions for the next thousands of years.

Future Space Missions

Travel to these distant Trojan asteroids was made possible due to the advancement of space technology over recent years. In 2021, NASA launched the Lucy mission for a 12-year journey to study the Jupiter Trojan asteroids.

On the other hand, the Earth Trojan asteroids have also been subjected to further studies and a potential site of mineral resources.

According to the study's co-author, Cesar Briceño, a researcher at the National Science Foundation's National Optical-Infrared Astronomy Research Laboratory (NOIRLab), "If we are able to discover more Earth Trojans, and if some of them can have orbits with lower inclinations, they might become cheaper to reach than our Moon."

Briceño added these asteroids may become ideal bases for advanced exploration of the solar system in the future and can potentially serve as a source of resources.  

Related article: Scientists Find New Trojan Asteroids Orbiting Neptune